Build planner · Poseidon Redwood · August 2026

Three upgrades
and one new bike

Main complaints: weight, and a general sluggishness. Both have a cheap fix and an expensive fix, and the gap between them is wider than it looks. Here’s what each option costs, what it changes about how the bike rides, and how much of the spend survives if a different frame shows up later.

Redwood, stock27.9 lbPublished test, no pedals
Stock rolling stock650b × 2.35Kenda Kadre, not tubeless
Stock top gear95.2″38t × 11–48, 10-speed
The Otso, as configured$2,50854 cm, Burnt Ochre, GRX 1×12

What each dollar buys

Cost against estimated weight
22 lb 24 lb 26 lb 28 lb $0 $1,000 $2,000 SPEND → ← LIGHTER THE BIKE NOW $0 · 27.9 lb A · TUBELESS TEST $180 · 25.9 lb est. B · 700c ALL-ROAD $830 · 24.2 lb est. B+ · ADD THE CRANKSET $940 · 23.2 lb est. C · FULL REBUILD $1,980 · 21.9 lb est. D · THE WARAKIN $2,508 · 22.2 lb est. Dashed line: the weight-per-dollar frontier. The two cheapest steps are the steepest. With a crankset in the mix, C and D are a tie on weight — 0.3 lb apart, inside the error bars — with $528 between them. So weight stops being the thing that decides this.

The 27.9 lb stock figure is a published measured weight. The rest are estimates built up from component weights, so read the vertical positions as ±0.5 lb. The horizontal positions are the reliable ones.

The crankset changes what this decision is about

The Redwood runs a square-taper crankset on a steel-spindle bottom bracket — together about 1,270 g. A two-piece MTB crank on an external BB, reusing the existing chainring, is around 780 g. That’s 1.1 lb for roughly $110, which makes it the second-best dollar-per-pound buy anywhere on this page.

It also erases the weight gap. With a crankset in it, the full rebuild lands at an estimated 21.9 lb against the Otso’s 22.2 — a difference well inside the margin of error on both numbers — for about $528 less.

So the honest version of this comparison isn’t about weight at all. Both routes get to roughly the same number. What $528 buys is a chromoly frame instead of a $850 aluminum one, a carbon fork matched to its own geometry, a five-year warranty, a bike worth something on resale, and no build weekends.

The four options

Parts, prices, and what actually changes
Option A · the cheap experiment

Go tubeless on the existing wheels

Answers most of the question for the price of a nice dinner out.

Spend$180
Est. weight25.9

Parts

ItemCost
650b × 47 supple tubeless tires, pair$135
Tape, valves, sealant$45
Total$180

The Redwood’s rims are already 26 mm internal and tubeless-ready. The Kadres bolted to them are not tubeless, and they’re around 900 g each with another 200 g of tube inside. That mismatch is the cheapest thing wrong with this bike.

What changes

  • Roughly 2 lb off, all of it rotating weight at the rim — the kind you feel on every acceleration
  • Large drop in rolling resistance: a supple casing instead of 2.35″ knobs
  • Lower pressures, better grip, no pinch flats

What doesn’t

  • Gear steps, brakes, riding position
  • Still a 650b bike, still reads mountain bike
Survives a new bike: the tires, if it runs 650b
Option B · best value on the board

700c all-road conversion

Wheels, tires and cockpit. Addresses both complaints for under a grand.

Spend$830+$110 w/ crank
Est. weight24.223.2 w/ crank

Parts

ItemCost
700c tubeless wheelset, 23–25 mm internal$450
700 × 40–45 supple tubeless tires$140
Tape, valves, sealant, rotors$90
40–42 cm bar, 12–16° flare$90
90–100 mm stem$60
Total$830
Optional: crankset + BB+$110

A 700 × 40 tire measures about 702 mm across, against about 703 mm for the stock 650b × 2.35. The wheel swap is geometrically free — nothing about the handling changes except that it gets faster. Going to 45 mm raises the bottom bracket about 5 mm.

On the crankset: a two-piece MTB crank with a 104 BCD spider takes the existing 38t ring straight across, so it’s arms and a bottom bracket only. About 1.1 lb for $110, which is the best value on this page after the tires. Take an MTB crank rather than road or GRX — the Redwood’s shell is 73 mm, and road cranks are built around 68 mm.

What changes

  • About 3.7 lb off the stock weight
  • The handlebar is the sleeper item. A 46 cm bar with 24° of flare on a 60–70 mm stem is most of why this bike feels like a drop-bar mountain bike rather than a fast gravel bike — note the Otso build spec goes to a 40 cm bar for exactly this reason
  • The Redwood’s stack is already low enough to support a road position; it just isn’t set up for one

What doesn’t

  • Gear steps of 15–17% at the fast end
  • Mechanical Tektro brakes
  • Heavy square-taper crank, aluminum fork
Survives a new bike: all of it
Option C · the full rebuild

Option B plus Rival AXS 1×12

Hydraulic brakes and tight road gearing. Wireless, so the frame’s 1×-only cable routing stops mattering.

Spend$1,980
Est. weight21.9

Parts, on top of Option B

ItemCost
Option B subtotal$830
Two-piece MTB crankset + 73 mm external BB$110
Rival AXS HRD levers + calipers (my used set — see note)$250
Rival XPLR rear derailleur$310
XG-1250 10–44 cassette, XDR driver$210
Flattop chain$40
Flattop-compatible 104 BCD chainring$80
AXS battery + charger$95
Hoses, barbs, olives, bleed kit$55
Total$1,980

The crankset isn’t optional here. A SRAM Flattop chain needs a Flattop-specific chainring, and while a 104 BCD Flattop ring exists, spending $80 on a ring to bolt onto a 1,270 g square-taper crank makes no sense when $110 more replaces the whole assembly and saves a pound.

Compatibility, in order of how easy it is to get wrong: MTB crank, not road — the shell is 73 mm. Non-Boost, 49 mm chainline — the rear is 142 mm, not 148. 170 mm arms to match what’s on there now.

What changes

  • Hydraulic braking, the biggest day-to-day gain anywhere on this page
  • Top gear from 95″ to about 111″, with single-tooth steps at the fast end
  • Wireless shifting sidesteps a frame that was never routed for a second derailleur

What it costs you

  • It ties the Otso on weight, so this is no longer a weight argument — it’s $528 saved against a better frame
  • Still an $850 aluminum frame with an aluminum fork, and close to nothing to sell at the end
  • Needs a shop or a confident home mechanic for the bleed, and nobody to call when something doesn’t fit
Survives a new bike: all of it
Option D · the build on the table

Otso Warakin Steel, 54 cm, Burnt Ochre

Turnkey, warrantied, and — as specced — the lightest bike on this page.

Spend$2,508
Est. weight22.2

The build

ComponentSpec
Frame4130 CrMo, 54 cm
ForkLithic Hiili carbon
WheelsDT Swiss G 1800
TiresG-One RS 700×45
DrivetrainGRX 600 1×12
Cassette / crank10–51T / 170 mm
Chainring42T Wolf Tooth
Bar / stem40 cm / 70 mm
Seatpost27.2 × 350 mm alloy
With discount$2,508

What changes

  • Roughly 5.7 lb lighter than the bike as it sits, hydraulic brakes, and a 42×10 top gear of about 118″
  • A carbon fork matched to the frame’s geometry — no axle-to-crown guesswork
  • Tuning Chip dropouts adjust the wheelbase 20 mm: short and lively for road, long for big tires and gear
  • Five-year frame warranty, real resale value, and it rides the day it arrives

What doesn’t

  • The chromoly frame is about 0.6 lb heavier than the Redwood’s aluminum one — the weight saving is fork, wheels and parts, not the frame
  • The 10–51 cassette leaves 20% gaps at the fast end. See the gearing section
  • The AXS parts I offered don’t get used
Project risk: none
Where I have a stake in this

Option C includes a used SRAM Rival AXS lever-and-caliper set that belongs to me, priced at $250. Worth knowing before that factors into anything:

The one option that uses my parts is the one this page argues against. That’s deliberate — better to ignore the parts entirely and pick the right bike than end up with a project because I had something to sell.

The gearing, and one thing to change

Gear inches, faster to the left
REDWOOD NOW · 38t × 11–48 · 10-SPEED · 650b × 2.35 95″ 22″ 15% 13% Four gears between 58″ and 95″. On a paved group ride that’s a 2–3 mph jump per shift — never quite the right gear, just the least wrong one. WARAKIN AS SPECCED · 42t × 10–51 · 700×45 118″ 23″ 20% 17% ← FASTER · EASIER →
Worth changing in the configurator

The 10–51 cassette is a mountain-bike range on a road-leaning bike. It buys a genuinely useful 23″ bailout gear, but the first two steps at the fast end are 20% and 17%wider than the gaps on the Redwood right now. If spirited pavement riding is the goal, that’s the one spec in this build working against it.

Shimano’s 12-speed 10–45 is the fix. Same 118″ top gear, single-tooth steps from 10 to 13 giving 8–10% jumps exactly where they’re wanted, and the low gear only rises from 23″ to about 26″. Still lower than the Redwood’s 22″? No — slightly higher. So the trade is real: tighter road gearing for a slightly less generous climbing gear.

Which way to go depends on the terrain. For long steep loaded climbs, keep the 10–51. For fast mixed rides where the frustration is gear steps, take the 10–45. Worth asking Otso whether the GRX 600 derailleur in this build supports both.

Dollars per pound

Every weight-saving change, ranked
ChangeCostSaved$ / lb
Tubeless conversion + supple tires$1802.0 lb$90
Two-piece crankset + BB$1101.1 lb$100
Carbon fork — see below$1801.4 lb$129
700c wheelset upgrade$4501.5 lb$300
Bar + stem$1500.2 lb$750
AXS drivetrain + brakes$1,0400.3 lb$3,470

Two things this makes obvious. The first two rows are almost all of the available weight for under $300 combined — tires and a crankset. And the AXS conversion is a terrible weight buy, which is fine, because weight isn’t what it’s for. It buys hydraulic brakes and tight gear steps. Judge it on those.

On the fork: it’s the third-cheapest pound on the list, and I’d still skip it. The Redwood’s stack is already low and most aftermarket carbon forks are shorter than the stock aluminum one, which would drop the front end further and quicken the steering against long chainstays. That’s before getting to unbranded carbon on the one component whose failure mode is face-first. Listed here because leaving it out would have been convenient rather than honest.

Notes on the build as configured

Component by component
Schwalbe G-One RS 700×45
The best choice in the build. This is Schwalbe’s fast gravel race tire — supple casing, quick compound, around 520 g. It’s precisely the kind of tire that Option A is trying to approximate on the Redwood, and it’s doing most of the work in the estimated weight and the ride feel.
40 cm Lithic Aventurine bar
70 mm Race Face stem
Right call, and it matters more than it looks. Going from a 46 cm bar with 24° of flare to a 40 cm bar is a large part of why this bike will feel road-oriented rather than mountain-derived. This is the change that Option B copies for $150.
27.2 × 350 mm alloy seatpost
A real comfort advantage. The Redwood uses a 31.6 mm post, which is stiff by diameter. A 27.2 post flexes meaningfully over rough surfaces, and it’s an easy later upgrade to carbon for another step in compliance.
DT Swiss G 1800 wheelset
Durable, serviceable, tubeless-ready, and easy to get parts for — but at roughly 1,850 g it’s the heaviest single decision in the build. This is where the remaining weight hides. A carbon wheelset would take 300–400 g out later without changing anything else, so it’s a good upgrade path to leave open rather than a problem to solve now.
GRX 600 1×12, 10–51T
The one spec to reconsider. See the gearing section above. Also note this cassette uses Shimano’s Micro Spline freehub standard, which is worth knowing for the future: Micro Spline wheels won’t take a SRAM cassette and vice versa, so it locks the wheel and drivetrain choices together down the road.
42T Wolf Tooth chainring
170 mm cranks
42×10 with a 45 mm tire gives about 118″ at the top, well beyond the Redwood’s 95″ — no spinning out on descents or fast group rides. Wolf Tooth is Otso’s sister company, machined in the same building, so support and spares are straightforward.

Geometry, overlaid

Redwood S and Warakin 54, aligned at the bottom bracket
POSEIDON REDWOOD · S 650b × 2.35 · 440 mm chainstay, fixed OTSO WARAKIN · 54 700 × 45 · drawn in the 430 mm mid chip position Head tube tops: 4 mm apart 565.7 / 377.8 vs 570 / 381 Head angle 71.2° vs 71.0° Trail 72.2 vs 72.9 mm Seat angle 74° vs 73° length not drawn to spec Chainstay 440 mm, fixed 420 / 430 / 440 — the two rings are the ends of that 20 mm range BB drop 63.4 vs 70.0 mm the Otso’s BB sits 6.6 mm lower Wheelbase 1032 vs 1033 mm in the mid chip position ground

Both frames are drawn to the same scale from published geometry, aligned at the bottom bracket, which is the conventional way to compare two frames. Wheels, both axles, the bottom bracket, the head tube and the fork are all positioned from real numbers. Seat tubes are drawn at their published angles but at an arbitrary length, since Otso doesn’t publish a seat tube length for the 54.

MeasurementRedwood SWarakin 54Δ
Stack565.7570+4.3
Reach377.8381+3.2
Head tube angle71.2°71.0°−0.2°
Seat tube angle74°73°−1.0°
Fork offset / axle-to-crown45 / 42047 / 420+2 / 0
Trail72.272.9+0.7
BB drop63.470+6.6
Chainstay440 fixed420 / 430 / 440up to −20
Wheelbase10321023 / 1033 / 1043±10
Stem, as specced6070+10
Bar width, as specced460 @ 24°400−60
Reach + stem437.8451+13.2

These are the same frame

Four millimetres of stack, three of reach, two tenths of a degree of head angle, and seven tenths of a millimetre of trail. The drawing makes it plain: the front triangles sit almost on top of each other. Whatever this decision is about, it is not about geometry, and the Warakin will not put you in a different position or steer noticeably differently. Any earlier suggestion on this page that the Otso would sit you more upright was wrong.

Two real differences, both at the back

The Otso’s bottom bracket sits 6.6 mm lower relative to its axles, which makes it feel a touch more planted in corners. More importantly, the Tuning Chip moves the rear axle through a 20 mm range — the two hollow rings on the drawing are the ends of it. Against a fixed 440 mm chainstay, being able to run 420 is a genuine change in how lively the bike feels, and it’s the one thing here that no amount of Redwood upgrading can replicate.

The cockpit is most of the felt difference

Reach to the hoods differs by 13 mm — noticeable but small. The bar is the big one: 400 mm against 460 mm with 24° of flare. That is a wholly different hand position and width, and it is most of why one of these will feel like a road-leaning gravel bike and the other like a drop-bar mountain bike. On the Redwood it costs about $150 to change, which is the strongest single argument for Option B on this page.

Size assumed. Drawn as a Redwood S, which is the closest match to a Warakin 54 by the numbers. An M is nearly as close: 570.7 stack / 384.4 reach, which is within 1 mm of stack and 3 mm of reach of the Otso — so the conclusion holds either way. Tell me the actual size and I’ll redraw it.

Data. Redwood figures are Poseidon’s published geometry; I verified them by computing front-centre from stack, reach, head angle, fork length and offset and getting 596.3 mm against their published 596.6, and trail figures that match exactly. Warakin figures are Otso’s published geometry with the size-54 wheelbase and Tuning Chip values confirmed in a review of that size. One caveat: Otso’s published stack, reach and head angle don’t quite reconcile with their published wheelbase — the two disagree by about 6 mm, implying a head angle nearer 70.4° than 71.0°. I’ve drawn the axles from the wheelbase figures, so the fork line carries roughly ±6 mm of uncertainty. Nothing large enough to change any conclusion above.

My read, and it’s only that

All three land somewhere reasonable. The question is what you’re buying.

If the money is the constraint

Start with A. $180 answers whether the tires were most of the problem, and it’s a fair bet they are. Then add the crankset for $110 — those two changes together are 3.1 lb for under $300, which is most of the available weight on this bike. Full Option B with a crankset is $940 and every part moves onto a future frame.

If the bike is the point

Buy the Warakin. The weight ends up a wash against a full rebuild, so what the extra $528 actually buys is a better frame, a matched fork, a warranty, resale value and zero weekends. That’s a fair price for those things. Just settle the cassette question before ordering.

C is a real option now

With a crankset it matches the Otso’s weight for about $528 less, so I can’t dismiss it on numbers. It loses on everything that isn’t a number: no warranty, nothing to sell at the end, a frame that will always be the cheapest part of the bike, and real wrench time. Worth it if building is part of the appeal. Not if it isn’t.

Answer these before spending anything

Six questions, all cheap to resolve
01
A bike, or a project?
The only question here that isn’t technical, and the one that decides the most. Every option except D involves parts sourcing, compatibility checking and at least one shop trip. Some people find that half the fun. If that’s not the appeal, that’s a completely sufficient reason to go straight to the Otso, and the rest of this is just context.
02
10–51 or 10–45?
The single most consequential thing left to decide on the Otso build, and it costs nothing to change before ordering. Steep loaded climbing favors the 10–51. Fast mixed-surface riding favors the 10–45.
03
If a crankset happens, three numbers to get right
73 mm English threaded shell, so an MTB crank and BB rather than road or GRX. Non-Boost with a 49 mm chainline, since the rear spacing is 142 mm. 170 mm arms to match what’s on there. A 104 BCD spider means the existing 38t narrow-wide ring bolts straight across, so it’s just arms and a bottom bracket — the cheapest pound on the bike after tires.
04
Does the 54 cm actually fit better?
On paper, no — it fits the same. A Warakin 54 is 570 stack / 381 reach; a Redwood S is 565.7 / 377.8 and an M is 570.7 / 384.4. Either way that is no meaningful difference, and the head angles are within two tenths of a degree. Where the Otso differs is the cockpit hung on it: a 70 mm stem and a 400 mm bar rather than a 60 mm stem and a 460 mm bar at 24° of flare. So if the current bike feels wrong in a fit sense, that’s worth chasing with a stem and bar rather than a frame. Still worth sitting on a 54 before ordering, since paper and bodies disagree regularly.
05
Tuning Chip or UDH on the steel frame?
Otso has moved the Warakin Ti to a UDH dropout. If the steel frame has followed, it affects which rear derailleurs fit later. Worth a question to Otso, especially since it interacts with the cassette decision.
06
What happens to the Redwood?
If the Otso wins, the Redwood is worth more sold intact than parted out, and it’s a genuinely good bike for someone getting started. Worth factoring the resale into the $2,508 — it isn’t nothing.